Blue Ram Hardware Expansion By Perkins Engineering For the Bally Arcade/Astrocade Video Overview created by BallyAlley. Video published May 18, 2018.
The Blue Ram expansion was created by Perkins Engineering. It was first released in 1980 as a 4KB RAM expansion for the Bally Arcade/Astrocade. The Blue Ram was originally meant as a stop-gap upgrade until Bally released the add-under (AKA the ZGRASS) keyboard/upgrade. When the add-under was never released, the Blue Ram became one of three available RAM upgrades for the Astrocade.
Here is some additional information about the Blue Ram from the Bally/Astrocade Game Cartridge and Hardware FAQ:
"The Blue Ram plugs into the 50-pin connector on the back of the Astrocade and expands the programming capabilities of the Astrocade. Available either fully assembled or as a kit, it was originally released in June, 1980 as a 4K unit. Over the next couple of years the memory capacity increased, so several different versions exist (4K, 8K, 16K and a small handful of 32K versions). Several confirmed accessories for this unit were released, including: keyboard, printer interface, modem interface, EPROM burner and BSR controller. The Blue Ram could be switched into a mode that simulated a cartridge; several of the third-party game cartridges were programmed using this unit and either the Machine Language Manager cartridge or the Blue Ram Utility."
This video covers the Blue Ram in detail, including explanations of how the extra hardware, such as the Blue Ram keyboard, plugs into the ZIF socket. Details of how the three toggle switches (Range, Mode and tape I/O) work are also provided. Without examples, it's hard to get a clear idea of what the Blue Ram can be used for by a user. Short videos of ten different pieces of software are shown that require a Blue Ram and are written in either Blue Ram BASIC or machine language (or a combination of both).
The ten videos that are shown after the explanation of the Blue Ram hardware are:
1) Four Blue Ram BASIC (BRB) games by WaveMakers (Mike Peace):